Improvement in casting steel



A' LDH-AGE' 2 Sheets--Sheet 1.

Casting Steel.

Patented June 5, 1866.

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, k2 Sheets-Sheet 2. A.A LOHAGE.

Casting Steel.

Patented June 5, 1866.

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UNITED STATES PATENT OFFICE.

ANTON LOHAGE, OF UNNA WESTPHALIA, PRUSSIA.

IMPROVEMENT IN CASTING STEEL.

To all whom it may concern Be it known that l', ANTON LOHAGE, of

Unna Westphalia, in the Kingdom of Prussia,-

have'invented Improvements in (lasting Steel; and I do hereby declare that the following is a full and exact description of my said invention.

This invention of improvements in casting steel has for its object the better preparation of the melted steel, especiallyin large masses, before it is poured or allowed to pass into the molds or into ingots. l

The invention is applicable to all steel in-a molten state, whether uniformly' or thoroughly melted or not, and whether melted by the old method in crueibles or otherwise, or produced b y the Bessemer' or other process, or partly by one process and partly by the other.

For the purpose of the invention I employ a furnace lined with reproof blocks made of material of as neutral a character as possible, the blocks being made to fit. The furnace is provided with a movable funnel made of lireproof material, through which funnel the molten metal is introduced into the interior of the furnace, as mentioned in the specification of patents granted to John Henry Johnson, bearing date 31st-of December, 1858, No. 3,007. The nose of this funnel reaches to the bottom of the bed of the furnace, or nearly so, and is in part cnt away on the part farthest away from the fireplace to allow the metal to iow out therefrom upon the bottom of the furnace. The furnace is heated by any wellknown method, preferringcoal or coal-gas,in combination with a blast, either hot or cold. I designate that point to which it is necessary to heat all steel in order to insure perfect and sound casting as overmelted77 or superheated The molten steal is conveyed through the funnel, which has been previously heated to a red-heat, into the furnace, the temperature of which has been raised to about the melting point of steel, preferring an excess of that heat to prevent any cooling of the mass.

It is important here to remark that I pour slag into the furnace, together with the steel, or previously melt slag in the furnace, in order to form a protecting-cover for the molten steel. The molten metal must be well covered with the slag, which may be obtained either from the melting-pots or'from the Bessemer process, or from previous meltin gs. This covering of slag is, as is well known, to prevent the flames or the blast from coming in direct contact with the molten steel, and is essential to the success of the operation. The heat of the furnace is kept up by means ofa fan or other blast till the metal is overmelted or superheated and the whole mass of molten steel has become thoroughly uniform. The metal is then run from the furnace through one or more tap-holes into a receiver or receivers which have been prevlonsly heated, (as is well known,) and when the metal is quiescent it is allowed to pass from the receiverinto the molds or into ingots. I continue the blast while pouring the molten steel into the furnace, while itis in the furnace, and while allowing it to run into the receiver or receivers, so as to keep it overmelted or superheated, and this I lcan do without injury to the steel by reason of the molten steel being' always eovered with slag.

The process above described I call an intermediate process, and by it I am enabled to gather together in the same furnace molten steel, whether uniformly or thoroughly melted or not, and whether melted in erucibles or in any other manner, or produced by the Bessemer or other process, or partly by one process and partly by the other, and make the same uniform for one or more castings or for forming` ingots of east-steel, by continuing the melting process till the mass is overmelted or superheated, thus enabling me to make castings of larger size and several castings or ingots of more equal temper than heretofore.

If the weight of molten steel run into the intermediate furnace is sufficient for the casting intended to be made, or if the temper of the steel does not require alteration, then the process need only be continued until it is overmelted or superheated and the mass has become thoroughly uniform.

The usual experience of a steel-melter, which tells him when the steel in crucibles is sufficiently melted for the purpose of casting, will enable him to ascertain when the mass in the intermediate furnace is overmelted or superheated 5 can also test the heat by inserting a rod of wrought-iron, and the rapidity of the action of the molten steel on the rod will show the practical melter when the mass is ready for pouring. If, however, the steel be insufficient in quantity, I add to the molten mass solid metal, (which I prefer to be previously heated,) either cast or wrought iron, or blister,

puddled, or scrap steel, taking care to main tain the temper of the steel required for the casting.

I alter the temper of the steel in the intermediate furnace and make the steel milder by the addition to the molten mass of wroughtiron or slightly-carbonized iron, which I prefer to be previously heated.

This power of making the temper of the steel in the intermediate furnace milder enables me to melt the steel in the crucibles (when steel melted in that way is used wholly or in part) harder' than is required for the casting, which is an advantage, as it quickens the melting and prevents the crucibles from being prematurely destroyed. I also alter the temper of the steel and make the steel in theinterniediate furnace harder by adding to the mass of molten metal more highly-carbonized solid metal, which I prefer to be previously heated.

When I add solid-thatis, unmolten-metal to the molten mass in the intermediate furnace, (and which I prefer to add gradually, and not altogether,) the process will necessarily take a longer time in the intermediate furnace before the steel is overmelted or superheated and the mass has become thoroughly uniform.

When it is desired to add spiegeleisen to the molten metal, as proposed by Mr. Mushet, I prefer to add it to the mass in the intermediate furnace, instead of in the Bessemer converting vessel, as heretofore practiced.

In all cases the process must be continued till the molten steel and the steel or iron added in the intermediate furnace is overmelted or snperheatcd and the mass has become uniform.

The practical experience of steel-melters will enable the operator to determine when the steel is ready for pouring.

When I operate on crucible-melted steel only, Iprefer tohave the top oftheintermediate furnace on a level with the door of the melting-house. It is not, however, necessary to show this arrangement by drawings.

When I operate on Bessemer steel, either alone or in conjunction with cruciblc-melted steel, I prefer to arrange the, works specially for the purpose. The intermediate process in all cases softens the steel slightly, which allows me, even if I intend no alteration of tem per in the intermediate furnace, to melt the steel in the Crucible harder in the first instance, which is an advantage.

In the accompanyingdrawings I have shown the furnace for carrying out my intermediate process, which however may be varied in form, and also the plan. I prefer for adapting my invention to steclworks in which the Bessemer process for making steel is employed.

Figure l, Sheet I, is a sectional elevation of apair of Bessemer converting-vessels, B B, conveniently arranged for the purposes of my invention. It will be seen that between the two vessels is placed a crane, A, provided with a receiving-vessel, C, into which the Bessemer metal is poured for the purpose of conveying it to the intermediate furnace, which is shown in longitudinal vertical section at Fig. 2. Fig. 3, Sheet II, is a transverse vertical section, showing the Bessemer converting-vessel B and the crane A, with the receiving-vessel C, from which the molten metal is being discharged into the intermediate'furnace,D. This figure also shows another crane, E, with another and larger receiving-vessel, F, into which the molten steel is run out from the intermediate furnace,D, and is conveyed by the crane E to the mold G to form the casting. rIhe vessels C and F should be heated before being used, as is well understood. Fig. 4. is a plan View of the whole arrangement, the intermediate furnace being shown in section. Fig. 5 is an end view of the furnace, and Fig 6 isa transverse vertical section of the same, showing the large receiving-vessel F placed ready to receive a charge of molten steel from the furnace D. The intermediate furnace,D, is built so far below the 'licor of the steel-inciting house that the top of the furnace coincides with the floor of the former. The pits H, to receive the mold G, are placed convenient to the furnace, and suitable foundations for cranes are also placed beneath the level of the iioor of the melting-house, as shown in the drawings.

In order to prepare the intermediate furnace for working, I commence by heating the furnace by the fuel in thefire-'place, to which end I open the doors a, Figs. 2 and 5, and by the natural draft thus obtained I bring up the heat to what I term almost a white heat.77 In order to afterward increase the heat I close the doors ct and open the valve b, Figs. 2 and 5, in the blast-conduit pipe. The blast is thus driven under the fire-bars by means of a fan or cylinder blast, and causes a very active combustion of the fuel, and the heat in the furnace is thereby much increased. In order to increase the heat still more, and to burn more completely all the gases arising from the fuel, two openings, c c, are made above the {ire-bridge, as seen in Figs. 2 and 4. A blast from any convenient source is made to pass through these openings, which are controlled by suitable stop-cocks. When l want to rake the fire to clear the tire-bars or to supply coals to the flreplace, the valve b must be closed and the door a, opened. The molten metal from the receiver C is poured into the intermediate furnace through the funnel d, which must be made redhot in a suitable oven before it is put into its place in the furnace, where it should be placed about fifteen minutes before it is required to be used.

The molten steel is pouredinto the intermediate furnace through the funnel d, and after the necessary quantity of metal is in the furnace the funnel is removed and the opening in the roof is closed by a removable lid or stopper. Before iilling the furnace with steel any cinder orother impurities which may have accumulated in it must be removed. Should any slag get into the exit-tine e of the furnace it is removed through the opening h. When the steel is ready for casting, the furnace is tapped at g g, and I prefer to provide two or more tap-holes, (two are shown in the drawings,) so that if it should be found desirable not to run olf the Whole charge ofmolten metal at one operation the tap hole or holes that has or have been used may be plugged up temporarily with tireclay, and as a tap-hole that has been used cannot readily be reopened in the same place, another tap-hole or other tapholes may be employed for running outthe remainder of the charge. ln order to operate upon steel melted in the ordinary crucibles or other melting-furnaces, I simply pour the contents of each crucible through the funnel d into the intermediate furnace, or I gather the contents of several crucibles in a receiver previously heated, and then emptyr that receiver into the intermediate furnace.

After the Bessemer process has been com` pleted inthecoixirertingyessels I em pty thecontents of the converter into the receiver (l, held by the crane A, as shown in Fig. l. The crane is then raised by means of hydraulic power, as is well known, and the receiver C is brought round over the funnel d ot' the intermediate furnace. rIhe plug C of the receiver C is then drawn up, and the receiver empties itself into the furnace, as shown at Fig. 3. After the steel has beensubjected to the required degree of heat in the intermediate furnace until it is overmelted or superheated it is allowed to tlow through the tap-holes g into the large receiver F, which is held by the crane E. When this receiver is brought over the mold G, placed in the pit H, Fig. 3, the steel is allowed to iow into the mold, as already explained. When it is desired to add to the steel coming from the Bessemer'convertiug-vessels steel melted in ordinary cruciblcs, either for the purpose of improving the quality or of increasing the quantity of the mass, the Crucible-melted steel may be poured by single crucibles or from a receiver into the intermediate furnace through the funnel d, either before or after the Bessemer steel has been poured into the intermediate furnace.

I can successively pour into my intermediate furnace the contents of two to four, or even more, of the Bessemer converting-vessels, according to the capacity of the furnace and the construction ol' the steel-works. The molten steel may remain half an hour or longer in the intermediate furnace, and in so long a time it is practicable to make a second conversion in the Bessemer converting-vessels, and this eX- tra quantity can be added to the first in the furnace.

1f it be desired to obtain access to the under side of the tire-bars while the furnace is in operation, this must be done from the ash-pit I in the air-channel, to which there are two doors, fand j", fitted air-tight, as shown in Fig. 2. The iireman enters through the doorf, and then closes the same and opens a slide or valve, t', of the second door, f', in order to counterbalance or equalize the pressure of air, after which the door j" may be opened. On returning, the fireman closes the door f and opens the slide i of the door j'. The compressed air in the space between the two doors will then escape, and the door f may be opened.

I would have it understood that I do not claim the particular furnace and accessories to the same hereinbcfore described and shown in the drawings; nor do I claim the special arrangement of the works hereinbefore described and shown in the drawings 5 but IVhat I do claim is. as follows, that is to sayl. The process hereinbefore described and called an intermediate process, whereby I continue the melting process till the mass is cverm'elted or superheated, made uniform, and ready for cast-ing.

2. The modes hereinbefore described of altering the temper of the molten steel in the intermediate process.

In witness whereof I, the said ANTON L0- HAGE, have hereunto set my hand and seal this 11th day of August7 A. I). 1865.

ANTON nonnen. iL. s]

Vitnesses:

J. M. HEIMANN,

)Asrnn BUGKNER. 

